Optical member and display device including the same

ABSTRACT

Disclosed are an optical member and a display device including the same. The optical member includes a receiving member; a host in the receiving member; and a plurality of wavelength conversion particles distributed in the host. The receiving member includes a light incident part having a first refractive index; and a light exit part having a second refractive index different from the first refractive index. The optical member improves the optical characteristics by adjusting the refractive indexes of the light incident part and the light exit part.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/982,916, filed Oct. 14, 2013; which is the U.S. national stageapplication of International Patent Application No. PCT/KR2011/009232,filed Nov. 30, 2011; which claims priority to Korean Application No.10-2011-0009833, filed Jan. 31, 2011, the disclosures of each of whichare incorporated herein by reference in their entirety.

TECHNICAL FIELD

The embodiment relates to an optical member and a display deviceincluding the same.

BACKGROUND ART

Recently, flat display devices, such as an LCD (liquid crystal display),a PDA (plasma display panel) or an OLED (organic light emitting diode),have been increasingly developed instead of conventional CRTs (cathoderay tubes).

Among them, the LCD includes a liquid crystal display panel having athin film transistor substrate, a color filter substrate and a liquidcrystal injected between the thin film transistor substrate and thecolor filter substrate. Since the liquid crystal display panel is anon-emissive device, a backlight unit is provided below the thin filmtransistor substrate to supply light. Transmittance of the light emittedfrom the backlight unit is adjusted according to the alignment state ofthe liquid crystal.

The backlight unit is classified into an edge-illumination typebacklight unit and a direct-illumination type backlight unit accordingto the position of a light source. According to the edge-illuminationtype backlight unit, the light source is located at a lateral side of alight guide plate.

The direct-illumination type backlight unit has been developed as thesize of the LCD has become enlarged. According to thedirect-illumination type backlight unit, at least one light source islocated below the liquid crystal display panel to supply the light overthe whole area of the liquid crystal display panel.

When comparing with the edge-illumination type backlight unit, thedirect-illumination type backlight unit can employ a large number oflight sources so that the high brightness can be achieved. In contrast,the direct-illumination type backlight unit must have thickness largerthan thickness of the edge-illumination type backlight unit in order toensure brightness uniformity.

In order to solve the above problem, a quantum dot bar having aplurality of quantum dots, which can convert blue light into red lightor green light, is positioned in front of a blue LED that emits the bluelight. Thus, as the blue light is irradiated onto the quantum dot bar,the blue light, the red light and the green light are mixed and themixed light is incident into the light guide plate, thereby generatingwhite light.

If the white light is supplied to the light guide plate by using thequantum dot bar, high color reproduction may be realized.

The backlight unit may include an FPCB (flexible printed circuit board)provided at one side of the blue LED to supply signals and power to theLEDs and a bonding member formed under the bottom surface of the FPCB.

The display device capable of displaying various images using the whitelight supplied to the light guide plate through the quantum dot bar asthe blue light is emitted from the blue LED has been extensively used.

BRIEF SUMMARY Technical Problem

The embodiment provides an optical member having an improved opticalcharacteristic and a display device including the same.

Technical Solution

An optical member according to one embodiment includes a receivingmember; a host in the receiving member; and a plurality of wavelengthconversion particles distributed in the host, wherein the receivingmember includes a light incident part having a first refractive index;and a light exit part having a second refractive index different fromthe first refractive index.

A display device according to one embodiment includes a light guideplate; a display panel on the light guide plate; a light source at alateral side of the light guide plate; and a wavelength conversionmember interposed between the light source and the light guide plate,wherein the wavelength conversion member includes a host; wavelengthconversion particles distributed in the host; and a receiving membersurrounding the host, and wherein the receiving member includes a lightincident part having a first refractive index and adjacent to the host;and a light exit part having a second refractive index different fromthe first refractive index, in which the host is sandwiched between thelight incident part and the light exit part.

A display device according to one embodiment includes a light guideplate; a display panel on the light guide plate; a light source at alateral side of the light guide plate; and a wavelength conversionmember interposed between the light source and the light guide plate,wherein the wavelength conversion member includes a plurality ofwavelength conversion particles to convert a wavelength of a lightemitted from the light source; and a receiving member to receive thewavelength conversion particles, and wherein the receiving memberincludes a light incident part disposed between the wavelengthconversion particles and the light source; and a light exit partdisposed between the wavelength conversion particles and the light guideplate and having a refractive index different from a refractive index ofthe light incident part.

Advantageous Effects

The optical member according to the embodiment includes a receivingmember having a light incident part and a light exit part, which has arefractive index different from that of the light incident part. Therefractive indexes of the light incident part and the light exit partcan be adjusted such that the optical member according to the embodimentmay have the optimum light incident efficiency and light exitefficiency.

The optical member according to the embodiment uses the receiving memberhaving various refractive indexes so that the light loss caused byreflection can be reduced and the light incident efficiency and thelight exit efficiency can be improved.

Further, the optical member according to the embodiment may furtherinclude an anti-reflection layer. In detail, the anti-reflection layeris disposed on the light incident part and the light exit part so thatthe light loss caused by reflection can be reduced and the lightincident efficiency and the light exit efficiency can be improved.

Therefore, the optical member according to the embodiment may have theimproved optical characteristics and the display device including theoptical member may have the improved brightness.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing an LCD according to thefirst embodiment;

FIG. 2 is a sectional view taken along line A-A of FIG. 1;

FIG. 3 is a perspective view of a wavelength conversion member accordingto the first embodiment;

FIG. 4 is a sectional view taken along line B-B′ of FIG. 3; and

FIGS. 5 to 9 are views showing the procedure for manufacturing awavelength conversion member.

DETAILED DESCRIPTION

In the description of the embodiments, it will be understood that when asubstrate, a frame, a sheet, a layer or a pattern is referred to asbeing on or under another substrate, another frame, another sheet,another layer, or another pattern, it can be directly or indirectly onthe other substrate; frame; sheet, layer, or pattern, or one or moreintervening layers may also be present. Such a position has beendescribed with reference to the drawings. The thickness and size of eachlayer shown in the drawings may be exaggerated, omitted or schematicallydrawn for the purpose of convenience or clarity. In addition, the sizeof elements does not utterly reflect an actual size.

FIG. 1 is an exploded perspective view showing an LCD according to thefirst embodiment, FIG. 2 is a sectional view taken along line A-A′ ofFIG. 1, FIG. 3 is a perspective view of a wavelength conversion memberaccording to the first embodiment; FIG. 4 is a sectional view takenalong line B-B of FIG. 3 and FIGS, 5 to 8 are views showing theprocedure for manufacturing the wavelength conversion member.

Referring to FIGS. 1 to 4, the LCD according to the embodiment includesa mold frame 10, a backlight unit 20 and a liquid crystal panel 30.

The mold frame 10 receives the backlight assembly 20 and the liquidcrystal panel 30 therein. The mold frame 10 has a rectangular frameshape and may include plastic or reinforced plastic.

In addition, a chassis may be disposed below the mold frame 10. Thechassis surrounds the mold frame 10 and supports the backlight assembly20. The chassis may also be disposed at a lateral side of the mold frame10.

The backlight assembly 20 is disposed in the mold frame 10 to supply thelight toward the liquid crystal panel 30. The backlight assembly 20includes a reflective sheet 100, a light guide plate 200, light emittingdiodes 300, a wavelength conversion member 400, a plurality of opticalsheets 500, and a flexible printed circuit board (ITCH) 600.

The reflective sheet 100 reflects the light upward as the light isgenerated from the light emitting diodes 300.

The light guide plate 200 is disposed on the reflective sheet 100. Thelight guide plate 200 guides the light upward by totally reflecting,refracting and scattering the light incident thereto from the lightemitting diodes 300.

The light guide plate 200 includes an incident surface directed towardthe light emitting diodes 300. From among lateral sides of the lightguide plate 200, a lateral side directed toward the light emittingdiodes 300 may serve as the incident surface.

The light emitting diodes 300 are disposed at the lateral side of thelight guide plate 200. In detail, the light emitting diodes 300 aredisposed at the incident surface.

The light emitting diodes 300 serve as a light source for generating thelight. In detail, the light emitting diodes 300 emit the light towardthe wavelength conversion member 400. In addition, the light emittingdiodes 300 may include a light emitting diode chip 310 and a fillingmaterial 320 covering the light emitting diode 310. Further, the lightemitting diodes 300 may further include a body for receiving the lightemitting diode chip 310 and a lead electrode electrically connected tothe light emitting diode chip 310.

The light emitting diodes 300 may include a blue light emitting diodegenerating the blue light or a UV light emitting diode generating the UVlight. In detail, the light emitting diodes 300 can emit the blue lighthaving the wavelength band of about 430 nm to about 470 nm or the UVlight having the wavelength band of about 300 nm to about 400 nm.

The light emitting diodes 300 are mounted on the FPCB 600. The lightemitting diodes 300 can be disposed under the FPCB 600. The lightemitting diodes 300 are driven by receiving a driving signal through theFPCB 600.

The wavelength conversion member 400 is interposed between the lightemitting diodes 300 and the light guide plate 200. In detail, thewavelength conversion member 400 is bonded to the lateral side of thelight guide plate 200. In more detail, the wavelength conversion member400 is attached to the incident surface of the light guide plate 200. Inaddition, the wavelength conversion member 400 can be bonded to thelight emitting diodes 300.

The wavelength conversion member 400 receives the light from the lightemitting diodes 300 to convert the wavelength of the light. Forinstance, the wavelength conversion member 400 can convert the bluelight emitted from the light emitting diodes 300 into the green lightand the red light. In detail, the wavelength conversion member 400converts a part of the blue light into the green light having thewavelength in the range of about 520 nm to about 560 nm, and a part ofthe blue light into the red light having the wavelength in the range ofabout 630 nm to about 660 nm.

In addition, the wavelength conversion member 400 can convert the UVlight emitted from the light emitting diodes 300 into the blue light,the green light and the red light. In detail, the wavelength conversionmember 400 converts a part of the UV light into the blue light havingthe wavelength in the range of about 430 nm to about 470 nm, a part ofthe UV light into the green light having the wavelength in the range ofabout 520 nm to about 560 nm, and a part of the UV light into the redlight having the wavelength in the range of about 630 nm to about 660nm.

Therefore, the white light may be generated by the light passing throughthe wavelength conversion member 400 and the lights converted by thewavelength conversion member. In detail, the white light can be incidentinto the light guide plate 200 through the combination of the bluelight, the green light and the red right.

As shown in FIGS. 2 to 4, the wavelength conversion member 400 includesa tube 410, a sealing member 420, a plurality of wavelength conversionparticles 430, a host 440, a first anti-reflection layer 460 and asecond anti-reflection layer 470.

The tube 410 receives the sealing member 420, the wavelength conversionparticles 430 and the host 440 therein. That is, the tube 410 may serveas a receptacle to receive the sealing member 420, the wavelengthconversion particles 430 and the host 440. In addition, the tube 410extends in one direction.

The tube 410 may have a rectangular pipe shape. In detail, a section ofthe tube 410, which is vertical to the length direction of the tube 410,may have the rectangular shape. The tube 410 may have a width of about0.6 mm and a height of about 0.2 mm. The tube 410 may include acapillary tube.

The tube 410 includes a light incident part 411 and a light exit part412. The light incident part 411 is integrally formed with the lightexit part 412. Although a boundary between the light incident part 411and the light exit part 412 is clearly shown in the drawings, theboundary between the light incident part 411 and the light exit part 412may be vague. In addition, the tube 410 may consist of the lightincident part 411 and the light exit part 412.

The light incident part 411 faces the light emitting diodes 300. Indetail, the light incident part 411 is opposite to the light exit part412 of the light emitting diodes 300. That is, the light incident part411 is closer to the light emitting diodes 300 than to the light exitpart 412. The light incident part 411 is disposed between the lightemitting diodes 300 and the wavelength conversion particles 430. Indetail, the light incident part 411 is disposed between the lightemitting diodes 300 and the host 440.

The light exit part 412 faces the light guide plate 200. In detail, thelight exit part 412 is opposite to the lateral side of the light guideplate 200. The light exit 412 is closer to the light guide plate 200than to the light incident 411. The light exit part 412 is disposedbetween the light guide plate 200 and the wavelength conversionparticles 430. In detail, the light exit part 412 is disposed betweenthe light guide plate 200 and the host 440.

The light incident part 411 faces the light exit part 412 whileinterposing the host 440 therebetween. That is, the host 440 is disposedbetween the light incident part 411 and the light exit part 412. Indetail, the host 440 is sandwiched between the light incident part 411and the light exit part 412.

The refractive index of the light incident part 411 is different fromthe refractive index of the light exit part 412. The light incident part411 and the light exit part 412 may have various refractive indexesaccording to the optical design. For instance, the first refractiveindex of the light incident part 411 may be lower than the secondrefractive index of the light exit part 412. To the contrary, the firstrefractive index of the light incident part 411 may be higher than thesecond refractive index of the light exit part 412.

The tube 410 is transparent. The tube 410 may include glass. In detail,the tube 410 may include a glass capillary tube. In addition, the lightincident part 411 and the light exit part 412 may include glass. At thistime, the glass used for the light incident part 411 has the ingredientdifferent from that of the glass used for the light exit part 412, sothat the refractive index of the light incident part 411 is differentfrom the refractive index of the light exit part 412. That is, therefractive index of the glass used for the light exit part 412 isdifferent from the refractive index of glass used for the light incidentpart 411.

The sealing member 420 is disposed in the tube 410, The sealing member420 is arranged at an end of the tube 410 to seal the tube 410. Thesealing member 420 may include epoxy resin.

The wavelength conversion particles 430 are provided in the tube 410. Indetail, the wavelength conversion particles 430 are uniformlydistributed in the host 440 installed in the tube 410.

The wavelength conversion particles 430 convert the wavelength of thelight emitted from the light emitting diodes 300. In detail, the lightis incident into the wavelength conversion particles 430 from the lightemitting diodes 300 and the wavelength conversion particles 430 convertthe wavelength of the incident light. For instance, the wavelengthconversion particles 430 can convert the blue light emitted from thelight emitting diodes 300 into the green light and the red light. Thatis, a part of the wavelength conversion particles 430 converts the bluelight into the green light having the wavelength in the range of about520 nm to about 560 nm and a part of the wavelength conversion particles430 converts the blue light into the red light having the wavelength inthe range of about 630 nm to about 660 nm.

In addition, the wavelength conversion particles 430 can convert the UVlight emitted from the light emitting diodes 300 into the blue light,the green light and the red light. That is, a part of the wavelengthconversion particles 430 converts the UV light into the blue lighthaving the wavelength in the range of about 430 nm to about 470 nm, anda part of the wavelength conversion particles 430 converts the UV lightinto the green light having the wavelength in the range of about 520 nmto about 560 nm. Further, a part of the wavelength conversion particles430 converts the UV light into the red light having the wavelength inthe range of about 630 nm to about 660 nm.

In other words, if the light emitting diodes 300 are blue light emittingdiodes that emit the blue light, the wavelength conversion particles 430capable of converting the blue light into the green light and the redlight may be employed. In addition, if the light emitting diodes 300 areUV light emitting diodes that emit the UV light, the wavelengthconversion particles 430 capable of converting the UV light into theblue light, the green light and the red light may be employed.

The wavelength conversion particles 430 may include a plurality ofquantum dots. The quantum dots may include core nano-crystals and shellnano-crystals surrounding the core nano-crystals. In addition, thequantum dots may include organic ligands bonded to the shellnano-crystals. Further, the quantum dots may include an organic coatinglayer surrounding the shell nano-crystals.

The shell nano-crystals can be prepared as at least two layers. Theshell nano-crystals are formed on the surface of the core nano-crystals.The quantum dots lengthen the wavelength of the light incident into thecore nano-crystals by using the shell nano-crystals forming a shelllayer, thereby improving the light efficiency.

The quantum dots may include at least one of a group-II compoundsemiconductor, a group-III compound semiconductor, a group-V compoundsemiconductor, and a group-VI compound semiconductor. In more detail,the core nano-crystals may include CdSe, InGaP, CdTe, CdS, ZnSe, ZnTe,ZnS, HgTe or HgS. In addition, the shell nano-crystals may includeCuZnS, CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe or HgS. The quantum dotmay have a diameter of about 1 nm to about 10 nm.

The wavelength of the light emitted from the quantum dots can beadjusted according to the size of the quantum dot or the molar ratiobetween the molecular cluster compound and the nano-particle precursorin the synthesis process. The organic ligand may include pyridine,mercapto alcohol, thiol, phosphine and phosphine oxide. The organicligand may stabilize the unstable quantum dots after the synthesisprocess. Dangling bonds may be formed at the valence band and thequantum dots may be unstable due to the dangling bonds. However, sinceone end of the organic ligand is the non-bonding state, one end of theorganic ligand is bonded with the dangling bonds, thereby stabilizingthe quantum dots.

In particular, if the size of the quantum dot is smaller than the Bohrradius of an exciton, which consists of an electron and a hole excitedby light and electricity, the quantum confinement effect may occur, sothat the quantum dot may have the discrete energy level. Thus, the sizeof the energy gap is changed. In addition, the charges are confinedwithin the quantum dot, so that the light emitting efficiency can beimproved.

Different from general fluorescent pigments, the fluorescent wavelengthof the quantum dot may vary depending on the size of the particles. Indetail, the light has the shorter wavelength as the size of the particlebecomes small, so the fluorescent light having the wavelength band ofvisible ray can be generated by adjusting the size of the particles. Inaddition, the quantum dot represents the extinction coefficient higherthan that of the general fluorescent pigment by 100 to 1000 times andhas the superior quantum yield, so that strong fluorescent light can begenerated.

The quantum dots can be synthesized through the chemical wet scheme.According to the chemical wet scheme, the particles are grown byimmersing the precursor material in the organic solvent, The quantumdots can be synthesized through the chemical wet scheme.

The host 440 surrounds the wavelength conversion particles 430. Indetail, the wavelength conversion particles 430 are uniformlydistributed in the host 440. The host 440 includes polymer. The host 440is transparent. That is, the host 440 includes transparent polymer.

The host 440 is disposed in the tube 410. In detail, the host 440 isfully filled in the tube 410. The host 440 may adhere to an innersurface of the tube 410.

An air layer 450 is formed between the sealing member 420 and the host440. The air layer 450 is filled with nitrogen. The air layer 450performs the damping function between the sealing member 420 and thehost 440.

The first anti-reflection layer 460 is disposed on the outer surface ofthe tube 410. In detail, the first anti-reflection layer 460 is disposedon the light incident part 411. The first anti-reflection layer 460 isdisposed between the tube 410 and the light emitting diodes 300. In moredetail, the first anti-reflection layer 460 is coated on the outersurface of the light incident part 411.

The first anti-reflection layer 460 reduces reflection of the lightincident thereto from the light emitting diodes 300. The firstanti-reflection layer 460 is transparent. The first anti-reflectionlayer 460 may include silicon oxide or silicon nitride. In addition, thefirst anti-reflection layer 460 may include magnesium fluoride (MgF2).Various materials having the proper refractive index can be used for thefirst anti-reflection layer 460 according to the optical design.

In addition, the first anti-reflection layer 460 may have variousthicknesses according to the optical design. For instance, the firstanti-reflection layer 460 may have a thickness in the range of about 100Å to about 800 Å.

The second anti-reflection layer 470 is disposed on the outer surface ofthe tube 410. In detail, the second anti-reflection layer 470 isdisposed on the light exit part 412. That is, the second anti-reflectionlayer 470 is disposed between the tube 410 and the light guide plate200. In more detail, the second anti-reflection layer 470 is coated onthe outer surface of the light exit part 412.

The second anti-reflection layer 470 improves the efficiency of thelight output from the tube 410. The second anti-reflection layer 470 istransparent. The second anti-reflection layer 470 may include siliconoxide or silicon nitride. In addition, the second anti-reflection layer470 may include magnesium fluoride (MgF2). Various materials having theproper refractive index can be used for the second anti-reflection layer470 according to the optical design.

In addition, the second anti-reflection layer 470 may have variousthicknesses according to the optical design. For instance, the secondanti-reflection layer 470 may have a thickness in the range of about 100Å to about 800 Å.

Referring to FIG. 2, the wavelength conversion member 400 is bonded tothe light emitting diodes 300. A first adhesive layer 101 is interposedbetween the wavelength conversion member 400 and the light emittingdiodes 300. The wavelength conversion member 400 can be bonded to thelight exit surface of the light emitting diodes 300 through the firstadhesive layer 101.

The wavelength conversion member 400 adheres to the first adhesive layer101. In detail, the first anti-reflection layer 460 adheres to the firstadhesive layer 101. In addition, the first adhesive layer 101 adheres tothe light emitting diodes 300. In more detail, the first adhesive layer101 adheres to the filling material 320. Thus, the air layer may not bepresent between the light emitting diodes 300 and the wavelengthconversion member 400. That is, the light incident part 411 adheres tothe light emitting diodes 300 through the first adhesive layer 101.

The first adhesive layer 101 is transparent. The first adhesive layer101 may include an epoxy resin or an acryl resin.

In addition, the wavelength conversion member 400 is bonded to the lightguide plate 200. A second adhesive layer 201 is interposed between thewavelength conversion member 400 and the light guide plate 200 and thewavelength conversion member 400 is bonded to the lateral side of thelight guide plate 200 through the second adhesive layer 201.

The wavelength conversion member 400 adheres to the second adhesivelayer 201. In detail, the second anti-reflection layer 470 adheres tothe second adhesive layer 201. In addition, the second adhesive layer201 adheres to the light guide plate 200. In detail, the second adhesivelayer 201 adheres to the lateral side of the light guide plate 200.Thus, the air layer may not be present between the light guide plate 200and the wavelength conversion member 400. That is, the light exit part412 adheres to the light guide plate 200 through the second adhesivelayer 201.

The second adhesive layer 201 is transparent. The second adhesive layer201 may include an epoxy resin or an acryl resin.

In this manner, the light emitted from the light emitting diodes 300 canbe incident to the light guide plate 200 through the wavelengthconversion member 400 without passing through the air layer due to thefirst and second adhesive layers 101 and 201.

The light generated from the light emitting diode chip 310 is incidentinto the light guide plate 200 by way of the filling material 320, thefirst adhesive layer 101, the first anti-reflection layer 460, the lightincident part 411, the host 440, the light exit part 412, the secondanti-reflection layer 470 and the second adhesive layer 201.

The refractive indexes of the filling material 320, the first adhesivelayer 101, the first anti-reflection layer 460, the light incident part411, the host 440, the light exit part 412, the second anti-reflectionlayer 470, the second adhesive layer 201 and the light guide plate 200must be properly adjusted in order to improve the light incidentefficiency to the light guide plate 200.

Since the tube 410 can be designed such that the refractive index of thelight incident part 411 may be different from the refractive index ofthe light exit part 412, the LCD according to the embodiment may havethe improved brightness.

For instance, the refractive indexes may become higher in the sequenceof the filling material 320, the first adhesive layer 101, the firstanti-reflection layer 460, the light incident part 411, the host 440,the light exit part 412, the second anti-reflection layer 470, thesecond adhesive layer 201 and the light guide plate 200.

That is, the refractive index of the light exit part 412 may be lowerthan that of the light guide plate 200. In addition, the refractiveindex of the light incident part 411 may be lower than that of the lightexit part 412. Further, the refractive index of the firstanti-reflection layer 460 may be lower than that of the light incidentpart 411. In addition, the refractive index of the secondanti-reflection layer 480 may be higher than that of the light exit part412. Further, the refractive index of the first adhesive layer 101 maybe lower than that of the light incident part 411. In addition, therefractive index of the second adhesive layer 201 may be higher thanthat of the light exit part 412.

To the contrary, the refractive indexes may become lower in the sequenceof the filling material 320, the first adhesive layer 101, the firstanti-reflection layer 460, the light incident part 411, the host 440,the light exit part 412, the second anti-reflection layer 470, thesecond adhesive layer 201 and the light guide plate 200.

In addition, the light incident part 411 may have the refractive indexbetween the refractive index of the host 440 and the refractive index ofthe filling material 320. In detail, the light incident part 411 mayhave the refractive index between the refractive index of the firstanti-reflection layer 460 and the refractive index of the host 440.

Further, the light exit part 412 may have the refractive index betweenthe refractive index of the host 440 and the refractive index of thelight guide plate 200. In detail, the light exit part 412 may have therefractive index between the refractive index of the host and therefractive index of the second anti-reflection layer 470.

In addition, the host 440 may have the refractive index between therefractive index of the light incident part 411 and the refractive indexof the light exit part 412.

The first anti-reflection layer 460 may have the refractive indexbetween the refractive index of the filling material 320 and therefractive index of the light incident part 411. In detail, the firstanti-reflection layer 460 may have the refractive index between therefractive index of the first adhesive layer 101 and the refractiveindex of the light incident part 411.

Further, the second anti-reflection layer 470 may have the refractiveindex between the refractive index of the light exit part 412 and therefractive index of the light guide plate 200. In detail, the secondanti-reflection layer 470 may have the refractive index between therefractive index of the light exit part 412 and the refractive index ofthe second adhesive layer 201.

In addition, the first adhesive layer 101 may have the refractive indexbetween the refractive index of the filling material 320 and therefractive index of the light incident part 411. In detail, the firstadhesive layer 101 may have the refractive index between the refractiveindex of the filling material 320 and the refractive index of the firstanti-reflection layer 460.

Further, the second adhesive layer 201 may have the refractive indexbetween the refractive index of the light exit part 412 and therefractive index of the light guide plate 200. In detail, the secondadhesive layer 201 may have the refractive index between the refractiveindex of the second anti-reflection layer 470 and the refractive indexof the light guide plate 200.

As a result, the layers 320, 101, 460, 411, 440, 412, 470, 201 and 200serving as a path for the light can be designed such that the differenceof the refractive index between adjacent layers can be minimized.

In this manner, the refractive indexes of the layers 320, 101, 460, 411,440, 412, 470, 201 and 200 serving as the path for the light areproperly adjusted through various schemes so that the LCD according tothe embodiment may have the high brightness.

The optical sheets 500 are disposed on the light guide plate 200 toimprove the characteristic of the light passing through the opticalsheets 500.

The FPCB 600 is electrically connected to the light emitting diodes 300.The FPCB 600 can mount the light emitting diodes 300 thereon. The FPCB600 is installed in the mold frame 10 and arranged on the light guideplate 200.

The mold frame 10 and the backlight assembly 20 constitute the backlightunit. That is, the backlight unit includes the mold frame 10 and thebacklight assembly 20.

The liquid crystal panel 30 is installed in the mold frame 10 andarranged on the optical sheets 500.

The liquid crystal panel 30 displays images by adjusting intensity ofthe light passing through the liquid crystal panel 30. That is, theliquid crystal panel 30 is a display panel to display the images. Theliquid crystal panel 30 includes a TFT substrate, a color filtersubstrate, a liquid crystal layer interposed between the above twosubstrates and polarizing filters.

FIGS. 5 to 8 are views showing the procedure for manufacturing thewavelength conversion member 400. The wavelength conversion member 400can be manufactured through the following method.

Referring to FIG. 5, the tube 410 including the light incident part 411and the light exit part 412 is formed. In detail, the light incidentpart 411 can be formed by drawing a first molten glass 410 a and thelight exit part 412 can be formed by drawing a second molten glass 410b.

In more detail, the tube 410 can be formed by simultaneously drawing andcooling the first molten glass 410 a and the second molten glass 410 b.At this tune, the ingredient of the first molten glass 410 a may bedifferent from the ingredient of the second molten glass 410 b.

Referring to FIG, 6, the wavelength conversion particles 430 areuniformly distributed in a resin composition 441. The resin composition441 is transparent. The resin composition 411 may have photo-curableproperty.

Then, internal pressure of the tube 410 is reduced, an inlet of the tube410 is immersed in the resin composition 441 in which the wavelengthconversion particles 430 are distributed, and ambient pressure isincreased. Thus, the resin composition 411 having the wavelengthconversion particles 430 is introduced into the tube 410.

Referring to FIG. 7, a part of the resin composition 441 introduced intothe tube 410 is removed and the inlet of the tube 410 becomes empty.Then, the resin composition 441 introduced into the inlet of the tube410 is cured by UV light so that the host 440 can be formed.

Referring to FIG. 8, epoxy resin composition is introduced into theinlet of the tube 410. Then, the epoxy resin composition is cured sothat the sealing member 420 is formed. The process for forming thesealing member 420 is performed under the nitrogen atmosphere, so theair layer 450 including nitrogen is formed between the sealing member420 and the host 440.

Referring to FIG. 9, the first anti-reflection layer 460 is formed onthe light incident part 411 through a vacuum deposition process and thesecond anti-reflection layer 470 is formed on the light exit part 412through the vacuum deposition process.

The first and second anti-reflection layers 460 and 470 can be formedjust after the tube 410 has been formed. That is, the first and secondanti-reflection layers 460 and 470 can be formed before the resincomposition 441 is introduced into the tube 410.

In this manner, the wavelength conversion member 400 is manufactured.

As described above, the tube 410 includes the light incident part 411and the light exit part 412 having refractive indexes different fromeach other. The refractive indexes of the light incident part 411 andthe light exit part 412 can be adjusted in such a manner that thewavelength conversion member 400 according to the embodiment may havethe optimum light incident efficiency and the light exit efficiency.

For instance, the host 440 may have the refractive index between therefractive index of the light incident part 411 and the refractive indexof the light exit part 412. In addition, the light exit part 412 mayhave the refractive index between the refractive index of the host 440and the refractive index of the light guide plate 200. Further, thelight guide plate 200 may have the refractive index higher than therefractive index of the light exit part 412, and the light exit part 412may have the refractive index higher than the refractive index of thelight incident part 411. In addition, the refractive index of thefilling material of the light emitting diodes 300 may be lower than therefractive index of the light incident part 411, and the refractiveindex of the light incident part 411 may be lower than the refractiveindex of the light exit part 412.

Therefore, the wavelength conversion member 400 can reduce the lightloss caused by reflection and can improve the light incident efficiencyand the light exit efficiency by using the tube 410 including the lightincident part 411 and the light exit part 412 having refractive indexesdifferent from each other.

The wavelength conversion member 400 can reduce the light loss caused byreflection and can improve the light incident efficiency and the lightexit efficiency by using the first and second anti-reflection layers 460and 470.

Therefore, the LCD according to the embodiment may have the improvedoptical characteristics and improved brightness.

Any reference in this specification to one embodiment, an embodiment,example embodiment, etc., means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the invention. The appearances of suchphrases in various places in the specification are not necessarily allreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anyembodiment, it is submitted that it is within the purview of one skilledin the art to effects such feature, structure, or characteristic inconnection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

INDUSTRIAL APPLICABILITY

The LCD according to the embodiments can be used in the display field.

What is claimed is:
 1. A backlight assembly comprising: a reflectivesheet; a light guide plate on the reflective sheet; an optical sheet onthe light guide plate; a light source disposed at a lateral side of thelight guide plate; a printed circuit board (PCB) on which the lightsource is disposed; and a wavelength conversion member disposed betweenthe light source and the light guide plate; wherein the wavelengthconversion member comprises: a tube; a host in the tube; an empty spacein the tube; and a plurality of wavelength conversion particles in thehost, wherein the tube comprises: a light incident part having a firstrefractive index and adjacent to the host; a light exit part having asecond refractive index; a first distal end; a second distal endopposite to the first distal end; a first tube portion; a second tubeportion adjacent to the first tube portion; and a midpoint between thefirst distal end and the second distal end along a first direction thatis parallel to a central longitudinal axis of the tube, wherein thefirst tube portion extends from the first distal end to the midpoint andcomprises the empty space and a portion of the host, wherein the secondtube portion extends from the midpoint to the second distal end andcomprises a portion of the host, wherein the light source comprises: alight emitting diode chip to generate a light; and a filling material tocover the light emitting diode chip, wherein the filling material has athird refractive index, wherein the light guide plate has a fourthrefractive index, wherein at least one of the first refractive index andthe second refractive index is different from the fourth refractiveindex, wherein the wavelength conversion particles comprise quantum dots(QDs), and wherein the tube extends continuously along the lateral sideof the light guide plate.
 2. The backlight assembly of claim 1, whereinthe light source includes a plurality of LEDs and wherein the LEDs aredisposed on a lateral side of the light guide plate.
 3. The backlightassembly of claim 1, wherein a length of the portion of the host of thefirst tube portion, taken in the first direction, is less than a lengthof the portion of the host of the second tube portion, taken in thefirst direction.
 4. The backlight assembly of claim 1, wherein the massof the portion of the host of the first tube portion is smaller than themass of the portion of the host of the second tube portion.
 5. Thebacklight assembly of claim 1, wherein the empty space includesnitrogen.
 6. The backlight assembly of claim 1, further comprising anadhesive part disposed between the PCB and the wavelength conversionmember.
 7. The backlight assembly of claim 1, wherein the fourthrefractive index is higher than at least one of the first refractiveindex and the second refractive index.
 8. The backlight assembly ofclaim 1, wherein the fourth refractive index is lower than at least oneof the first refractive index and the second refractive index.
 9. Thebacklight assembly of claim 1, at least one of the first refractiveindex and the second refractive index is higher than the thirdrefractive index.
 10. The backlight assembly of claim herein at leastone of the first refractive index and the second refractive index islower than the third refractive index.
 11. The backlight assembly ofclaim 1, wherein the tube includes glass.
 12. A display devicecomprising: a frame; a backlight assembly on the frame; a liquid crystalpanel on the backlight assembly; wherein the backlight assemblycomprises: a reflective sheet; a light guide plate on the reflectivesheet; an optical sheet on the light guide plate; a plurality of LEDsdisposed at a lateral side of the light guide plate; a printed circuitboard (PCB) on which the light source is disposed; and a wavelengthconversion member disposed between the light source and the light guideplate; wherein the wavelength conversion member comprises: a tube; ahost in the tube; an empty space in the tube; and a plurality ofwavelength conversion particles in the host, wherein the tube comprises:a light incident part having a first refractive index and adjacent tothe host; a light exit part having a second refractive index; a firstdistal end; a second distal end opposite to the first distal end; afirst tube portion; a second tube portion adjacent to the first tubeportion; and a midpoint between the first distal end and the seconddistal end along a first direction that is parallel to a centrallongitudinal axis of the tube, wherein the first tube portion extendsfrom the first distal end to the midpoint and comprises the empty spaceand a portion of the host, wherein the second tube portion extends fromthe midpoint to the second distal end and comprises a portion of thehost, wherein the LED comprises: a light emitting diode chip to generatea light; and a filling material to cover the light emitting diode chip,wherein the filling material has a third refractive index, wherein thelight guide plate has a fourth refractive index, wherein at least one ofthe first refractive index and the second refractive index is differentfrom the fourth refractive index, wherein the wavelength conversionparticles comprise quantum dots (QDs) and wherein the tube extendscontinuously along the lateral side of the light guide plate.
 13. Thedisplay device of claim 12, wherein a length of the portion of the hostof the first tube portion, taken in the first direction, is less than alength of the portion of the host of the second tube portion.
 14. Thedisplay device of claim 12, wherein the mass of the portion of the hostof the first tube portion, taken in the first direction, is smaller thanthe mass of the portion of the host of the second tube portion.
 15. Thedisplay device of claim 12, wherein the empty space includes nitrogen.16. The display device of claim 12, further comprising an adhesive partdisposed between the PCB and the wavelength conversion member.
 17. Thedisplay device of claim 12, wherein the fourth refractive index ishigher than at least one of the first refractive index and the secondrefractive index.
 18. The display device of claim 11, wherein the fourthrefractive index is lower than at least one of the first refractiveindex and the second refractive index.
 19. The display device of claim12, wherein at least one of the first refractive index and the secondrefractive index is higher than the third refractive index.
 20. Thedisplay device of claim 12, wherein the tube includes glass.